Hello, yet another problem with my '08 SS has come up. Whenever I start my car, it starts to make a knocking sound. However, whenever I turn the car off and back on, it either decreases in volume or goes away altogether. I have no idea what this could be, and I'm not getting any codes to help narrow it down.

I took a video, but the file was too large for the site, so I uploaded it to youtube. Here's the link;
What could this be, and is my car okay to drive? Thanks

 

I would suggest that you don't drive it until you pop the cam cover off and look at the timing chain; any slack between the sprockets is bad.

 

If it had something to do with the timing chain, wouldn't it continue to do that even after turning the car off and back on?

 

No. The main symptom of a bad timing chain is "rattles on start goes away on warm up".

 

After you turn the ignition off then restart the engine you can still hear the noise faintly, could be timing chain slack, could be HPFP noise have a listen up on the driver’s side of the cylinder head.

 

Forgot about the High Pressure Fuel Pump. It is cam driven and makes noise when failing.

 

I thought the timing chain (and HPFP) were more like chatter than this knocking sound on the video.

 

Need a video from under the hood. Move the camera around so we can try to pinpoint where the noise is coming from.

 

Will do. I listened to it under the hood and I can't really tell where it's coming from, but I'll take a video in the morning anyway.

 

You should be able to feel that with a finger.